Adding System.FilePath

[Jeffrey Yasskin]

On 3/19/07, Simon Peyton-Jones <simonpj at microsoft.com> wrote:
> | > base isn't compatible between major ghc versions (6.6/6.8). so you may
> | > use only base 2.0 with 6.6 or base 3.0 with 6.8.
> |
> | This seems wrong to me (though I'm quite new at this, so there could
> | be something obvious I'm missing). I understand that ghc-6.6 expects
> | certain types and functions to be defined at particular places within
> | base, but most names aren't like that. One could declare that base-2.x
> | defines all the magic names in the places ghc-6.6 expects them, but
> | other names can be moved around between 2.x and 2.(x+1). Then ghc-6.8
> | would expect the names where base-3.x places them, and so on.
>
> That's more or less it.  I documented this here
>         http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/WiredIn
>
> In the vocabulary of that page
> * You can change neither the definition nor the location of wired-in things
> * You can change the definition, but not the location, of known-key or Orig-RdrName things
>
> By "location" I mean the name and defining module.
>
> The Wiki page tells you how to find out exactly which names fall into which category.
>
> Does that help?  If anything is unclear, let's improve the Commentary
>
> | So, to solve the immediate problem you're complaining about, it might
> | be more practical to pull the "bottom" (GHC/Prim*.hs) out of base into
> | something like ghc-prim for ghc-6.8 rather than to prevent new modules
> | from being added to the top.
>
> We have considered doing that.  But I don't follow how it would help you here.

Thanks, Simon, I hadn't realized it was already possible to release a
new base version for the same compiler. The ghc-prim suggestion is
probably irrelevant then.

To resolve the deadlock around System.FilePath, I propose that Neil be
allowed to submit it to base (so that it's definitely in a logical
package for ghc-6.8 even if the rest of the refactoring doesn't
happen), and then Bulat and anyone else who wants to use it before
then should release base-2.1 with System.FilePath backported.

Does that sound reasonable?

Jeffrey